1. Field of the Invention
The present invention relates to an optoelectronic device and the method for manufacturing the same and, more particularly, to an optoelectronic device and the method for manufacturing the same, which the optoelectronic effect such as light emission or light reception can be enhanced by forming a dual-structural nano dot to increase the confinement density of electrons and holes.
2. Description of the Prior Art
As application fields of the optoelectronic device, there are a light emitting device, a light receiving device, an optical guide, an optical modulating device, and a spi-LED. Also, as applications using the devices, there are a silicon ULSI, an optical switch, OEIC (Optoelectronic Integrated Circuit) to which optical signals is applied, and an optical computer and a quantum computer circuit to which a solar battery or an optical operation circuit is provided.
Hereinafter, the conventional optoelectronic device using the nano dot will be described with reference to FIG. 1. The general light emitting device has a simple structure which nano dots are formed in silicon or compound semiconductor. In the optoelectronic device in FIG. 1, a hole injection layer 2 is formed on an electron injection layer 1, and the nano dots 6 are formed in hole injection layer 2 near to the interface between the electron injection layer 1 and the hole injection layer 2.
The conventional optoelectronic device has a limitation in that the structures of the energy bands of the nano dot 6 and the electron and bole injection layers 1 and 2 confine carriers. Due to an indirect band gap of the nano dot 6, the efficiency thereof is low. Furthermore, Since the electrons and the holes have not locally confined at the periphery of the nano dots, the carriers are recombined at the interface between the electron injection layer 1 and the hole injection layer 2. It leads the generated light to spread out with undesired wavelength. And, in case where the electron and the hole injection layers are recombined with the indirect transition type, the recombination does not lead to emit the light, so it is transformed into a type of heat energy. Accordingly, the conventional optoelectronic device comes to have a low efficiency, a high leakage current, and low reliability.
To increase the quantum efficiency, the injected minority carriers must be converged to the nano dots when the forward voltage is applied to the PN junction. However, in case where the structure of the energy band of the nano dot is the stagger type, in which the injection and the confinement of the electron and the hole are not accomplished well, the probability of the recombination of the carriers is low. Accordingly, the development of a new device having high quantum efficiency has been required.